With two days to go before their spring training opener, the Marlins got the good news they were hoping for regarding Giancarlo Stanton, their leading home run hitter and lone All-Star last season.

But the player who finished right behind Stanton in terms of power — center fielder Justin Ruggiano — left practice early Thursday with tightness in his lower back, and it is unclear if he will be ready to go when the Marlins open Grapefruit League action Saturday at Roger Dean Stadium against the Cardinals.

“My lower back kind of tightened up a little bit fielding ground balls,” said Ruggiano, who hit .313 with 13 homers and 36 RBI in 91 games for the Marlins last season — arguably the best surprise in a disappointing season. “Instead of pushing it [Thursday] being so early in camp I came in to see if we can’t get it settled now. It’s not fun. It’s annoying. I’m frustrated and angry. I don’t have a hold on why it keeps happening.”

Ruggiano, a favorite to land the starting center field job, battled lower back pain last season. He also banged up his shoulder and didn’t play again after Sept. 21.

“I know it’s not that anything is wrong with my back,” he said. “I had an X-ray and MRI on that, so I know it’s nothing structural. It’s muscular.

“As soon as I can get back out there, I’m getting back out there.”

Stanton, plunked on the back of his head by a fastball that got away from top prospect Jose Fernandez on Wednesday, was in good spirits Thursday morning — and feeling better.

“It all checked out fine,” Stanton said of the precautionary X-rays of his neck taken after practice Wednesday. “I was pretty loopy, I must say, [Wednesday]. But for the most part I feel fine. [I’m] back.”

Manager Mike Redmond said Stanton hit in the cage and went through a workout with the team but didn’t participate in the simulated games later Thursday afternoon. Stanton is expected to return to practice Friday and play Saturday against the Cardinals.

MORRISON Update

Logan Morrison took his first steps toward getting back on the field Thursday by wearing an antigravity bubble below his waist and jogging in about 30-second intervals on a treadmill.

The first baseman, who had surgery five months ago to repair a torn patellar tendon in his right knee for the second time, said doctors do not want him hitting or doing any other baseball activities yet. They told him to only use the treadmill until his knee strengthens.

“I just know I’m running [Thursday] on the treadmill and then after that I don’t know what’s going on,” Morrison said. “They don’t want me hitting right now because if it does get sore, they want to know what is making it sore.”

Morrison said the treadmill work will progress for about a month — assuming there aren’t any setbacks. His agent told The Miami Herald this week that the hope is Morrison will be game ready by April 15. Morrison said that has not changed.

SPRING ROTATION SET

Redmond has set his pitching rotation for the first nine spring games:

John Maine will start Saturday against the Cardinals in Jupiter. Henderson Alvarez goes Sunday against Washington in Viera and March 1 against the Twins in Jupiter. Wade LeBlanc will pitch Monday against the Braves in Orlando.

Ricky Nolasco, Miami’s projected Opening Day starter, will pitch Tuesday against the Mets in Jupiter and again March 2 against the Mets in Port St. Lucie. Nathan Eovaldi will go Wednesday against Washington in Viera and March 3 against the Mets in Jupiter. Jacob Turner starts Thursday against the Cardinals in Jupiter.

• Redmond said former Marlins teammate Mike Lowell is scheduled to arrive in Jupiter next Thursday. Lowell has agreed to serve as a guest assistant coach for a three-game stretch that begins then. Redmond said he’s still working to get Luis Castillo, the team’s all-time leader in hits, to also come and serve as a guest assistant coach.

“Luis is going to be a game-time decision,” Redmond said. “He’s either just going to show up someday or we’re going to have to go down and get him.”

• The Marlins wrapped up the second of two days of simulated intrasquad games. Shortstop Adeiny Hechavarria tripled off Alvarez and scored. Second baseman Donovan Solano had two hits.

“A couple of those guys look like they’re ready to go for Opening Day already,” Redmond said. “I don’t know how they do that. They come out swinging.

“We had a lot of good at-bats. I thought we pitched well, too. It was good to see [ Braulio] Lara go up there and throw strikes. [ Arquimedes] Caminero threw some nasty pitches. [ Kevin] Slowey pitched well. Alvarez [too].”